I can start a new project .. but only my saved project is showing this issue
If you can start and open another project and the opening problem exists with only the one project, there is a strong possibility that there is corrupt media event in your project.
One possible way to identify the offending event is to start a new project, select the media folder of the project in VP's Explorer window with the thumbnail display option selected, and if any video or audio event only displays as an icon rather than with a sample of the image, then that is very likely the problem event.